Manga, or comic, is a popular art form and medium of entertainment over the world. It is unique in its elegant use of rich sets of screens, and a tidy and fine drawing style.
FIG. 1 shows the typical workflow of manga background production. First, artists decide the perspective and roughly sketch the major structure of the scene with pencils (Step 101). Next, they finalize the line drawing with ink (Step 102). With the precise lines in place, artists then begin the screening procedure. They select the appropriate screen papers to express shading, tone, texture, or atmosphere. The screen is overlaid on the target region, and then it is carefully cut along the boundaries and pasted on the region (Step 103), until all the regions are overlaid with their screens. After that, the final manuscript is ready for print (Step 104).
Such a line drawing and screening process done by manga artists is tedious and labor intensive. The task is rather tedious and labor-intensive, especially when large amount of irregular regions exist.
Therefore, it is required to provide a computer-assisted method for converting color photographs to manga-style images.